There are many circumstances in which it is necessary or desirable to releasably grip one or more items having an elongated portion so that it may be moved from one location to another, or spread across a desired area. For example, in the electrical and telecommunication industries, wires or cables, such as fiber optic cables and copper power and telecommunication wires, are often pulled through one or more conduits. The conduit may have any desired length and location, such as underground, through buildings, overhead and even inside vehicles and machines. The wires or cables may be single strand or include multiple lines. A single telephone cable, for example, may include five hundred twisted copper wires surrounded by insulation and plastic sheathing.
Depending upon the application, one or more enhancements to existing technology may improve the ability to move the items. For examples, the item(s) being moved may be very heavy or the desired path may be very long, requiring a significant pulling force that the gripping device and method must support. For yet other examples, centering the elongated item in the gripping device, or gripping one or more inside surfaces of the elongated items may enhance or expand the ability to move items. For still a further example, it is sometimes preferable to pull multiple lines at the same time.
It should be understood that the above-described examples, features and/or disadvantages are provided for illustrative purposes only and are not intended to limit the scope or subject matter of the claims of this patent or any patent claiming priority hereto. Thus, none of the appended claims or claims of any related patent should be limited by the above discussion or construed to address, include or exclude the cited examples, features and/or disadvantages, except and only to the extent as may be expressly stated in a particular claim.
Accordingly, it would be desirable to have apparatus and methods for gripping at least one elongated item and having one or more of the following features, capabilities or attributes: includes gripping members having multiple grippers; includes gripping members capable of projecting outwardly to engage at least one inside portion of at least one elongated item; includes at least one biasing member associated with at least one gripping member; includes biasing members associated with gripping members to restrict movement of the associated gripping members in one direction; includes biasing members associated with gripping members to facilitate engagement of the associated gripping members with an elongated item; includes multiple gripping members disposed upon a common carrier; includes pairs of gripping members mounted upon common pins, respectively; assists in centering the elongated item in the apparatus; assists in centering at least one elongated item in the bore of the apparatus to enhance gripping of the elongated item(s) by gripping members; prevents undesirable or damaging penetration of an elongated item by gripping members; includes at least one centering device that assists in preventing non-engagement of the gripping members with at least one elongated item; includes at least one centering device capable of preventing gripping members from penetrating the elongated item more than desired; includes gripping members that assist in centering the elongated item; prevents gripping members from being too far tangential relative to an elongated item associated with the apparatus; prevents gripping member from skidding along the outside of an elongated item associated with the apparatus; is capable of gripping different diameter elongated items; is capable of gripping a greater range of outer diameter cables; is capable of gripping elongated items with different insulation thicknesses; is capable of gripping a non-end portion of an elongated item; includes at least one attachment device for facilitating pulling the apparatus and which does not obstruct the passage of an elongated item entirely through the apparatus; is capable of connecting multiple axially aligned gripping devices that grip a common elongated item; provides a flexible connector between multiple axially aligned gripping devices that grip a common elongated item; allows multiple gripping devices to be axially connected to increase pulling capacity; allows multiple gripping devices to be axially connected to enhance the gripping of the elongated item; allows multiple gripping devices to be axially connected to provide movement flexibility of the elongated items; allows multiple gripping devices to be axially connected to accommodate non-linear pulling paths, such as turns or curves; allows pulling heavy elongated items; allows pulling elongated items over a long path; allow pulling elongated items under significant drag forces; allows gripping members to cut through one or more insulation layers of an elongated items and deform, without undesirably damaging, the core of the elongated item; includes non-rotating gripping members; includes fixed position gripping members; includes a body formed of multiple pieces that may be disassembled; includes a clam shell-like, or split body, arrangement allowing ease of disengagement with an elongated item; or a combination thereof.